MECHANISM OF ETCH-STOP IN HIGH-ASPECT-RATIO CONTACT HOLE ETCHING

Citation
T. Ohiwa et al., MECHANISM OF ETCH-STOP IN HIGH-ASPECT-RATIO CONTACT HOLE ETCHING, JPN J A P 1, 37(9A), 1998, pp. 5060-5063
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Applied
Volume
37
Issue
9A
Year of publication
1998
Pages
5060 - 5063
Database
ISI
SICI code
0021-4922(1998)37:9A<5060:MOEIHC>2.0.ZU;2-Z
Abstract
The mechanism of etch stop in contact hole etching has been studied. I t was found that ill high aspect ratio holes, even though the incident ions lose charge due to collision with the sidewall, they are able to bombard the bottom of the hole maintaining their high energy. It was also confirmed that the redeposition of sputtered species From the flu orocarbon polymer on the hole sidewall induces the etch stop at the bo ttom of the high-aspect hole. Furthermore, it was observed that etch s top occurs at higher aspect ratios for the same hole diameter in oxide films with higher boron and phosphorous dopant concentrations. This i s explained by the effective removal of etch-inhibiting carbon species due to the release of more oxygen at a higher etch rate in highly dop ed oxide film. In conclusion, the etch stop in a high-aspect-ratio hol e is determined by the balance between the effects of high-energy-spec ies bombardment and etch inhibition of carbon species.